JP2017132604A - Post-processing device and image formation apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a post-processing device which can be miniaturized and in which the quality of folding processing can be improved, and an image formation apparatus having the same.SOLUTION: A post-processing device includes: a folding roller pair 2 which performs folding processing to a sheet; conveyance means which conveys the sheet to the folding roller pair; and a guide member 6 which guides binding of the sheet to the vicinity of a nip of the folding roller pair 2. The guide member 6 has a planar shape. A tip 61 that is an end on the downstream side in the conveyance direction of the sheet in the guide member 6 has a recessed shape when viewed from the normal direction of a principal surface of the guide member 6.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a post-processing apparatus and an image forming apparatus including the post-processing apparatus. More specifically, the present invention relates to a post-processing apparatus that performs a folding process on a sheet and an image forming apparatus including the post-processing apparatus.

  The electrophotographic image forming apparatus includes a scanner function, a facsimile function, a copying function, a function as a printer, a data communication function, and a server function, an MFP (Multi Function Peripheral), a facsimile apparatus, a copying machine, a printer, and the like. is there.

  2. Description of the Related Art Post processing apparatuses that perform post processing on paper printed by an image forming apparatus are known. The post-processing apparatus is usually attached to the image forming apparatus, but there are some which can operate alone. The processing that can be executed by the post-processing device includes bookbinding processing for saddle-stitching and folding a plurality of sheets at the center, Z-folding processing for folding a large page into a Z shape, and dividing a large page into three equal parts. For example, there are three fold processing, folding a paper, and stapling.

  As a method for performing folding processing on a sheet, there is a method in which a deflection (loop) is formed on the sheet and the deflection is sent to the nip of a pair of folding rollers. In this method, there is a problem in that the folding position is not stable because it is impossible to always form the same shape of bending on the paper.

  Patent Document 1 below discloses a sheet processing apparatus including a pressing member including a roller and a support member that rotatably supports the roller. This sheet processing apparatus, when performing bending processing on a sheet material, holds the pressing member on the sheet material along the upper guide plate while maintaining the state in which the pressing member presses the sheet material against the upper guide plate. Move. Thereby, the folding position of the sheet material is guided to the sheet folding roller.

JP 2005-67741 A

  According to the technique of Patent Document 1, since the deflection of the sheet can be fed into the nip of the pair of folding rollers using the pressing member, the folding position can be controlled and the folding position is stabilized. On the other hand, in the technique of Patent Document 1, since the tip of the guide member has a roller shape, the configuration of the apparatus is complicated. As a result, the technique disclosed in Patent Document 1 causes an increase in the size of the apparatus, which in turn increases the cost.

  In addition, in the technique of Patent Document 1, when the distortion in the width direction of the paper occurs in the deflection, the shape of the deflection cannot be corrected. For this reason, when the paper is folded at the nip of the pair of folding rollers, the paper is wrinkled and damaged, and the quality of the folding process is lowered.

  SUMMARY An advantage of some aspects of the invention is that it provides a post-processing device that can be reduced in size and an image forming apparatus including the post-processing device.

  Another object of the present invention is to provide a post-processing device capable of improving the quality of folding processing and an image forming apparatus provided with the post-processing device.

  A post-processing apparatus according to an aspect of the present invention includes a pair of folding rollers that performs a folding process on a sheet, a conveyance unit that conveys the sheet to the pair of folding rollers, and guides the deflection of the sheet to the vicinity of the nip of the pair of folding rollers. The guide member has a plate-like shape, and the front end portion, which is the end portion of the guide member on the downstream side in the sheet conveyance direction, is viewed from the normal direction of the main surface of the guide member. It has a concave shape.

  Preferably, in the post-processing apparatus, the tip portion includes both end portions in the width direction that is a direction orthogonal to the transport direction when viewed from the normal direction of the main surface of the guide member, and a central portion that is a portion other than both end portions. And both end portions project downstream in the transport direction from the central portion.

  Preferably, in the post-processing apparatus, the length in the width direction of the central portion is shorter than the length in the width direction of the minimum sheet to be folded.

  Preferably, in the post-processing apparatus, the length of the guide member in the normal direction decreases from the upstream position in the transport direction by a predetermined distance from the tip portion toward the tip portion.

  Preferably, the post-processing apparatus further includes a biasing member that biases the guide member toward the nip of the pair of folding rollers.

  Preferably, in the post-processing apparatus, the guide member swings about the axis.

  Preferably, the post-processing apparatus further includes another pair of folding rollers that performs a first folding process on the paper, the pair of transport rollers and the pair of folding rollers transport the paper along the transport path, and the pair of folding rollers is The second folding process is performed on the sheet on which the first folding process has been performed, the guide member can be moved to the shielding position, and the shielding position is the circumference of one of the rollers constituting the other folding roller pair. This is the position where the guide member shields the conveyance path from the region between the position closest to the conveyance path in the direction and the position closest to the conveyance path in the circumferential direction of the other roller constituting the other pair of folding rollers.

  Preferably, in the post-processing apparatus, the guide member is a retracted position that exists upstream of the shielding position in the transport path in the transport direction, and is further movable to a retract position that exposes the transport path in at least a part of the region. is there.

  An image forming apparatus according to another aspect of the present invention includes an image forming apparatus main body that performs printing on a sheet, and the post-processing apparatus that performs post-processing on the sheet printed on the image forming apparatus main body.

  According to the present invention, it is possible to provide a post-processing apparatus that can be reduced in size and an image forming apparatus including the post-processing apparatus. Further, it is possible to provide a post-processing device capable of improving the quality of the folding process and an image forming apparatus including the post-processing device.

1 is a diagram schematically illustrating an appearance of an image forming apparatus 100 according to an embodiment of the present invention. It is sectional drawing which shows schematic structure of the folding apparatus 40 vicinity in the post-processing apparatus 51 of FIG. It is sectional drawing which shows the structure of the folding apparatus 40 in one embodiment of this invention. It is a perspective view which shows the structure of the guide member 6 vicinity in one embodiment of this invention. It is a top view which shows the structure of the guide member 6 in one embodiment of this invention. It is sectional drawing which shows the structure of the guide member 6 in one embodiment of this invention. FIG. 2 is a block diagram showing a control configuration of image forming apparatus 100 in an embodiment of the present invention. It is sectional drawing which shows the 1st operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing explaining the shielding position P61 of the guide member 6 in one embodiment of this invention. It is sectional drawing which shows the 2nd operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 3rd operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 4th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 5th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 6th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 7th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 8th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 9th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 10th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 11th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 12th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows 13th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 14th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is sectional drawing which shows the 15th operation | movement of the post-processing apparatus 51 in one embodiment of this invention. It is a figure explaining the effect of one embodiment of the present invention. It is a top view which shows the structure of the guide member 6 in the modification of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the following embodiment, a case where the post-processing device is a part of an image forming apparatus will be described. Examples of the image forming apparatus include an MFP, a printer, a copier, and a facsimile. The post-processing apparatus is configured separately from the image forming apparatus main body, and may be detachable from the image forming apparatus main body as necessary.

  FIG. 1 is a diagram schematically illustrating the appearance of an image forming apparatus 100 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration in the vicinity of the folding device 40 in the post-processing device 51 of FIG.

  Referring to FIGS. 1 and 2, image forming apparatus 100 in the present embodiment includes a post-processing device 51 and an image forming device main body 52. The image forming apparatus main body 52 performs printing on paper. The post-processing device 51 includes a folding device 40 and the like. The folding device 40 is provided inside the housing of the post-processing device 51. The post-processing device 51 can perform a Z-folding process on the paper printed by the image forming apparatus main body 52 using the folding device 40.

  FIG. 3 is a cross-sectional view showing the configuration of the folding device 40 in one embodiment of the present invention.

  Referring to FIG. 3, the folding device 40 includes a conveyance roller pair 1 (an example of a conveyance unit), a folding roller pair 2 (an example of a folding roller pair), and a folding roller pair 3 (an example of another folding roller pair). A folding guide 4, a guide member 6, a paper guide 7, and a sensor SE.

  The transport roller pair 1 is disposed in a transport path TR1 (an example of a transport path) that is a path for transporting paper. The conveyance roller pair 1 is rotationally driven, and conveys the sheet to the folding roller pair 2 or 3 along the conveyance path TR1 with the sheet sandwiched at the nip N1.

  The folding roller pair 2 is arranged on the downstream side in the paper transport direction with respect to the transport roller pair 1 in the transport path TR1. The pair of folding rollers 2 is rotationally driven and transports along the transport path TR1 with the sheet sandwiched by the nip N2. The pair of folding rollers 2 performs the second folding process (second folding process) at the nip N2 on the sheet to be Z-folded.

  The folding roller pair 3 is disposed in the transport path TR2. The transport path TR2 is a transport path branched from the transport path TR1 between the transport roller pair 1 and the folding roller pair 2. The pair of folding rollers 3 performs the first folding process (first folding process) at the nip N3 on the sheet to be Z-folded.

  The folding guide 4 guides the deflection of the sheet to the vicinity of the nip N3 of the pair of folding rollers 3 when the first folding process is performed on the sheet on which the Z folding process is performed. The folding guide 4 is movable between a retracted position and a folding position. Details of the retracted position and the folding position will be described later.

  The guide member 6 guides the sheet to the vicinity of the nip N2 of the pair of folding rollers 2 when the sheet that is not subjected to the Z-folding process is transported along the transport path TR1. The guide member 6 guides the deflection of the sheet to the vicinity of the nip N2 of the pair of folding rollers 2 when the second folding process is performed on the sheet on which the Z folding process is performed. The guide member 6 swings between a shielding position, a retracted position, and a guide position about a fulcrum FC (an example of a shaft). Details of the shielding position, the retracted position, and the guide position will be described later.

  The paper guide 7 guides the paper to the transport path TR1. The paper guide 7 has an opening 7a at a branch portion of the transport path TR2 in the transport path TR1.

  The sensor SE detects paper on the downstream side of the nip N2 in the transport path TR1.

  Further, the post-processing device 51 includes a fixing portion 31 that is a portion to which the folding guide 4 is fixed, a biasing member 32 provided between the folding guide 4 and the fixing portion 31, and a portion to which the guide member 6 is fixed. And a urging member 34 provided between the guide member 6 and the fixing portion 33. The post-processing device 51 moves the folding guide 4 by driving the fixing unit 31. The post-processing device 51 moves the guide member 6 by driving the fixing portion 33.

  In addition, as for conveyance roller pair 1, one roller which comprises conveyance roller pair 1 may be rotationally driven, the other roller may be driven by one roller, and both rollers which comprise conveyance roller pair 1 rotate. It may be driven. The same applies to the method of rotational driving of each of the folding roller pairs 2 and 3.

  FIG. 4 is a perspective view showing a configuration in the vicinity of the guide member 6 according to the embodiment of the present invention. FIG. 5 is a plan view showing the configuration of the guide member 6 according to the embodiment of the present invention. In FIG. 4, an arrow MD1 indicates the sheet conveyance direction, an arrow W indicates the width direction of the guide member 6, and an arrow T indicates the thickness direction of the guide member 6 (the method of the main surface of the guide member 6). Line direction). The directions indicated by each of the arrow MD1, the arrow W, and the arrow T are orthogonal to each other. Hereinafter, the direction indicated by the arrow W may be referred to as the width direction, and the direction indicated by the arrow T may be referred to as the thickness direction. FIG. 5 is a plan view when viewed from the thickness direction.

  4 and 5, the guide member 6 has a plate-like shape and has two main surfaces whose normal direction is the thickness direction (in FIGS. 4 and 5). Only one main surface is visible). The guide member 6 does not include a roller for pressing the paper. Arms 8 extending in the thickness direction are provided at both ends in the width direction of the guide member 6. A shaft portion 9 is provided at the position of the fulcrum FC. The arm portion 8 suspends the guide member 6 from the shaft portion 9. An insertion hole 8a is formed in the arm portion 8, and the shaft portion 9 is inserted into the insertion hole 8a.

  The guide member 6 has a tip portion 61. The leading end portion 61 is an end portion on the downstream side in the sheet transport direction when viewed from the thickness direction. The tip portion 61 has a concave shape. Specifically, the tip portion 61 includes an end portion 61a, an end portion 61b, and a center portion 61c. The end portions 61 a and 61 b are both end portions in the width direction of the tip end portion 61. The central portion 61c is a portion other than the end portions 61a and 61b in the distal end portion 61. Each of the end portions 61a and 61b protrudes downstream of the central portion 61c in the paper transport direction. Accordingly, when performing the second folding process on the sheet on which the Z folding process is performed, the guide member 6 can push the deflection of the sheet to the vicinity of the nip N2 at the end portions 61a and 61b.

  The length WG in the width direction of the central portion 61c is preferably shorter than the length WS in the width direction of the minimum sheet to be folded. As a result, the sheet to be folded can be reliably pushed by the end portions 61a and 61c.

  Note that the fixed portion 33 (FIG. 3) may be the shaft portion 9. The urging member 34 (FIG. 3) may be a coil spring attached to the shaft portion 9. The guide member 6 may be provided with a bent portion, an opening portion, a convex portion, or a concave portion as necessary.

  As an example of the size of the guide member 6, the depth (notch depth) WD of the central portion 61c is 1 mm, and the length WG in the width direction of the central portion 61c is 167 mm. The shape, depth, and length in the width direction of the central portion 61c are arbitrary.

  FIG. 6 is a cross-sectional view showing the configuration of the guide member 6 in one embodiment of the present invention.

  Referring to FIG. 6, the thickness of guide member 6 (the length in the direction indicated by arrow T) is a predetermined distance D from front end portion 61 toward the front end portion 61 from the upstream side in the paper transport direction. is decreasing.

  FIG. 7 is a block diagram showing a control configuration of the image forming apparatus 100 according to the embodiment of the present invention.

  Referring to FIG. 7, an image forming apparatus 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a scanner 104, a network interface 105, and an operation. A panel 106, an auxiliary storage device 107, an image forming unit 108, and a post-processing control unit 109 are included. The CPU 101, the ROM 102, the RAM 103, the scanner 104, the network interface 105, the operation panel 106, the auxiliary storage device 107, the image forming unit 108, and the post-processing control unit 109 are mutually connected by a bus or the like.

  The CPU 101 operates according to the control program and controls the entire image forming apparatus 100.

  The ROM 102 stores a control program.

  A RAM 103 is a working memory for the CPU 101 and temporarily stores various data.

  The scanner 104 reads an image of a document.

  The network interface 105 transmits and receives information to and from an external device connected to the image forming apparatus 100 through a network (not shown).

  The operation panel 106 displays various information and accepts various operations.

  The auxiliary storage device 107 stores various data such as image data to be printed.

  The image forming unit 108 performs printing on a sheet inside the image forming apparatus main body 52. The image forming unit 108 is roughly composed of a toner image forming unit, a fixing device, a paper transport unit, and the like. The image forming unit 108 forms an image on a sheet by, for example, electrophotography. The toner image forming unit combines four color images by a so-called tandem method, and forms a color image on a sheet. The toner image forming unit includes a photoconductor provided for each color of C (cyan), M (magenta), Y (yellow), and K (black), and an intermediate in which a toner image is transferred (primary transfer) from the photoconductor. The image forming apparatus includes a transfer belt and a transfer unit that transfers an image from the intermediate transfer belt to a sheet (secondary transfer). The fixing device has a heating roller and a pressure roller. The fixing device conveys the sheet on which the toner image is formed between the heating roller and the pressure roller, and heats and presses the sheet. As a result, the fixing device melts the toner adhering to the paper and fixes it on the paper to form an image on the paper. The paper transport unit includes a paper feed roller, a transport roller, and a motor that drives them. The paper transport unit feeds paper from the paper feed cassette and transports it inside the image forming apparatus main body 52. The paper transport unit introduces the paper printed by the image forming apparatus main body 52 from the image forming apparatus main body 52 into the post-processing device 51.

  The post-processing control unit 109 controls the overall operation of the post-processing device 51 under the control of the CPU 101. The post-processing control unit 109 includes a conveyance roller pair control unit 111, a folding roller pair control unit 112, a folding roller pair control unit 113, a folding guide control unit 114, and a guide member control unit 115. The transport roller pair control unit 111 controls the rotation of the transport roller pair 1. The folding roller pair control unit 112 controls the rotation of the folding roller pair 2. The folding roller pair control unit 113 controls the rotation of the folding roller pair 3. The folding guide control unit 114 controls the operation of the folding guide 4. The guide member control unit 115 controls the operation of the guide member 6.

  Subsequently, the operation of the post-processing device 51 in the present embodiment will be described. In the following drawings, a part of the configuration of the post-processing device 51 may be shown only when explanation is necessary.

  With reference to FIG. 8, the image forming apparatus 100 carries the paper discharged from the image forming apparatus main body 52 into the post-processing device 51 and conveys the paper into the folding device 40.

  When the post-processing device 51 transports the paper SH into the folding device 40, the post-processing device 51 transports the paper SH along the transport path TR1 by rotating each of the transport roller pair 1 and the folding roller pair 2. During this conveyance, the folding guide 4 is present at the retracted position P41. The retreat position P41 is a position where the tip 4a of the folding guide 4 is present at an upper position of the transport path TR1 (on the opposite side of the folding roller pair 3 in the transport path TR1). The guide member 6 exists in the shielding position P61.

  FIG. 9 is a cross-sectional view illustrating the shielding position P61 of the guide member 6 according to the embodiment of the present invention.

  Referring to FIGS. 8 and 9, the shielding position P61 is the position PO1 closest to the transport path TR1 in the circumferential direction of one roller 3a constituting the folding roller pair 3 and the other one constituting the folding roller pair 3. This is a position where the guide member 6 shields the transport path TR1 from a region RG between the roller 3b and the position PO2 closest to the transport path TR1 in the circumferential direction.

  When the guide member 6 is present at the shielding position P <b> 61, the guide member 6 guides the leading edge of the sheet conveyed from the conveyance roller pair 1 to the folding roller pair 2. When the guide member 6 is present at the shielding position P61, the sheet conveyed along the conveying path TR1 is prevented from coming into contact with the pair of folding rollers 3, and a sheet passing defect is prevented from occurring.

  When the Z-folding process is not performed on the paper SH, the post-processing device 51 continues to rotate each of the conveying roller pair 1 and the folding roller pair 2 in a state where the guide member 6 exists at the shielding position P61, and the arrow MD1 The sheet SH is discharged to a discharge tray 21 (FIG. 1) existing on the downstream side of the nip N2 shown. On the other hand, when the Z-folding process is performed on the paper SH, the post-processing device 51 performs the operations shown in FIGS. 10 to 23 following the operation of FIG.

  Referring to FIG. 10, when the post-processing device 51 detects the leading edge of the paper SH by the sensor SE, the post-processing device 51 moves the guide member 6 in the direction indicated by the arrow AR1 and arranges it at the retracted position P62. The retreat position P62 is a position that exists on the upstream side of the shielding position P61 in the transport path TR1. When the guide member 6 moves to the retracted position P62, at least a part of the region RG is exposed to the transport path TR1.

  Further, the post-processing device 51 stops the pair of folding rollers 2 at the timing when the leading end of the sheet SH reaches a predetermined position determined according to the size of the sheet SH and the type of the folding mode. The position of the leading edge of the sheet SH is calculated based on the time when the leading edge of the sheet SH is detected by the sensor SE and the conveyance speed of the sheet SH. The post-processing device 51 continues to rotationally drive the transport roller pair 1 even after the folding roller pair 2 is stopped.

  Referring to FIG. 11, the sheet SH is sent in the direction of the folding roller pair 2 by the conveying roller pair 1, and therefore, a deflection (loop) LP <b> 1 is formed in the vicinity of the nip N <b> 3 in the sheet SH. The post-processing device 51 stops the conveying roller pair 1 after a predetermined time t1 has elapsed since the folding roller pair 2 was stopped. The time t1 is set to a time such that the deflection LP1 having an appropriate size is formed on the paper SH based on the type and basis weight of the paper SH.

  Since the deflection LP1 is formed by feeding only the transport roller pair 1, the variation in the stop position of the sheet is smaller than when the deflection is formed by feeding both the transport roller pair 1 and the folding roller pair 2. can do.

  Next, the post-processing device 51 performs the first folding process with the guide member 6 disposed at the retracted position P62. The post-processing device 51 starts moving the folding guide 4 toward the folding position P42 near the nip N3, as indicated by the arrow AR2. The post-processing device 51 guides the deflection LP1 of the paper SH to the nip N3 by pressing the paper SH with the folding guide 4.

  Referring to FIG. 12, post-processing device 51 moves folding guide 4 by moving fixing unit 31 by distance d1. When the folding guide 4 moves, the apex of the deflection LP1 is pushed by the lower end of the folding guide 4 and approaches the nip N3. The urging member 32 urges the folding guide 4 toward the nip N3 of the pair of folding rollers 3. The tension of the sheet SH increases, and the reaction force of the sheet SH received by the biasing member 32 also increases. Then, the tension of the sheet SH is balanced with the urging force of the urging member 32 before the fixed portion 31 moves by the distance d1. A part of the movement amount (distance d1) of the fixing portion 31 thereafter is absorbed as the contraction amount of the urging member 32. As a result, the amount of movement of the folding guide 4 at the time of FIG. 12 becomes smaller than the distance d1, and the amount of contraction of the urging member 32 becomes larger than before the movement of the folding guide 4 starts. That is, the urging member 32 functions as a relief mechanism for the folding guide 4. Due to the action of the urging member 32, it is possible to avoid a situation in which the folding guide 4 applies an excessive force to the sheet SH and the sheet SH is damaged.

  Since the size of the deflection LP1 before being pushed by the folding guide 4 can be adjusted by the time t1 as described above, it does not become excessively large compared to the deflection space (the space near the nip N3). Therefore, the sheet SH is not wrinkled or bent, and the bending LP1 can be always pushed with sufficient force by the folding guide 4.

  Referring to FIG. 13, post-processing device 51 moves deflection SH1 of sheet SH along conveyance path TR2 while fixing portion 31 is moved by distance d1 (with deflection LP1 held by folding guide 4). Then, each of the conveying roller pair 1 and the folding roller pair 2 is rotated in the direction of feeding downward, and the folding roller pair 3 is rotated in the direction of feeding the deflection LP1 of the sheet SH downward along the conveying path TR2.

  When the sheet SH is fed into the nip N3, the deflection LP1 increases and the tension of the sheet SH decreases. The urging force of the urging member 32 becomes larger than the tension of the paper SH, and the urging member 32 returns to its original length. Due to the urging force when the urging member 32 returns to its original length, the folding guide 4 moves again toward the nip N3 and further pushes in the deflection LP1 as indicated by the arrow AR3.

  The folding guide 4 finally reaches the folding position P42. The folding position P42 reached by the folding guide 4 may be any position where the tip 4a of the folding guide 4 is present on the side of the pair of folding rollers 3 in the transport path TR1, and the position where the sheet SH is pushed into the nip N3. It may be a position where the sheet SH is guided to the vicinity of the nip N3.

  Referring to FIG. 14, after the folding guide 4 is disposed at the folding position P42, the deflection LP1 is bitten by the nip N3, and a first fold is formed on the sheet SH (first folding process).

  Referring to FIG. 15, after the first fold is formed on paper SH, post-processing device 51 moves fold guide 4 as indicated by arrow AR4 and returns it to retracted position P41.

  Referring to FIG. 16, in the first folding process, the leading end of the sheet SH moves in the direction indicated by the arrow MD2 along the transport path TR1, so the post-processing device 51 detects the sheet SH by the sensor SE. Detect the tip again. The post-processing device 51 stops the pair of folding rollers 2 and 3 at the timing when the leading end of the sheet SH reaches a predetermined position determined according to the size of the sheet SH and the type of folding mode. The position of the leading edge of the sheet SH is calculated based on the time when the leading edge of the sheet SH is detected by the sensor SE and the conveyance speed of the sheet SH. The post-processing device 51 continues to rotationally drive the transport roller pair 1 even after the folding roller pair 2 is stopped.

  Referring to FIG. 17, the sheet SH is fed in the direction of the folding roller pair 2 by the transport roller pair 1, and therefore, a deflection (loop) LP <b> 2 is formed near the nip N <b> 2 in the sheet SH. The post-processing device 51 stops the conveying roller pair 1 after a predetermined time t2 has elapsed since the folding roller pairs 2 and 3 were stopped. The time t2 is set to such a time that the deflection LP2 having an appropriate size is formed on the paper SH based on the type and basis weight of the paper SH.

  Next, the post-processing device 51 performs the second folding process with the folding guide 4 placed at the retracted position P41. The post-processing device 51 starts moving (swinging) the guide member 6 toward the guide position P63 in the vicinity of the nip N2, as indicated by an arrow AR5. The post-processing device 51 guides the deflection LP2 of the paper SH to the nip N2 by pressing the paper SH with the guide member 6.

  Referring to FIG. 18, post-processing device 51 moves guide member 6 by moving fixing portion 33 by distance d2. When the guide member 6 moves, the apex of the deflection LP2 is pushed by the tip of the guide member 6 and approaches the nip N2. When the guide member 6 swings, the contact portion of the guide member 6 with the paper SH changes with the swing. The urging member 34 urges the guide member 6 toward the nip N2 of the folding roller pair 2. The tension of the paper SH increases, and the reaction force of the paper SH received by the urging member 34 also increases. Then, the tension of the sheet SH is balanced with the urging force of the urging member 34 before the fixing portion 33 moves by the distance d2. A part of the movement amount (distance d2) of the fixing portion 33 thereafter is absorbed as the contraction amount of the urging member 34. As a result, the amount of movement of the guide member 6 at the time of FIG. 18 becomes smaller than the distance d2, and the amount of contraction of the urging member 34 becomes larger than before the movement of the guide member 6 starts. That is, the urging member 34 functions as a relief mechanism for the guide member 6. Due to the action of the urging member 34, it is possible to avoid a situation in which the guide member 6 applies an excessive force to the sheet SH and damages the sheet SH.

  Since the size of the deflection LP2 before being pushed by the guide member 6 can be adjusted by the time t2 as described above, it does not become excessively large compared to the deflection space (the space near the nip N2). Therefore, the sheet SH is not wrinkled or bent, and the deflection LP2 can always be pushed by the guide member 6 with sufficient force.

  Referring to FIG. 19, the post-processing device 51 feeds the deflection LP2 of the sheet SH into the nip N2 with the fixing portion 33 moved by the distance d2 (with the deflection LP2 held by the guide member 6). Each of the conveying roller pair 1 and the folding roller pair 2 is rotated, and the folding roller pair 3 is rotated in the direction in which the paper SH is fed upward.

  When the deflection LP2 of the sheet SH is fed into the nip N2, the deflection LP2 increases and the tension of the sheet SH decreases. The urging force of the urging member 34 becomes larger than the tension of the sheet SH, and the urging member 34 returns to its original length. Due to the urging force when the urging member 34 returns to its original length, the guide member 6 moves again toward the nip N2, and further pushes the deflection LP2 as indicated by an arrow AR6.

  The guide member 6 finally reaches the guide position P63. Note that the guide position P63 to which the guide member 6 reaches may be any position existing on the downstream side of the shielding position P61 in the transport path TR1, and may be a position where the sheet SH is pushed into the nip N2. The position where the sheet SH is guided to the vicinity of the nip N2 may be used.

  Referring to FIG. 20, after the guide member 6 is disposed at the guide position P63, the deflection LP2 is bitten by the nip N2, and a second fold is formed on the sheet SH (second folding process).

  Referring to FIG. 21, after the second fold is formed on the paper SH, the paper SH is conveyed by the pair of folding rollers 2 in the direction indicated by the arrow MD1. When the post-processing device 51 detects the leading edge of the paper SH by the sensor SE, the post-processing device 51 moves the guide member 6 in the direction indicated by the arrow AR7 and arranges it at the shielding position P61 in order to prepare for the next job.

  Referring to FIGS. 22 and 23, the paper SH on which the second fold is formed (Z-folded) may be discharged to the discharge tray 21 as it is, or other than Z-folding processing such as stapling and punching. Post-processing may be performed.

  [Effect of the embodiment]

  FIG. 24 is a diagram for explaining the effect of the embodiment of the present invention.

  Referring to FIG. 24 (a), according to the present embodiment, since the leading end portion 61 of the guide member 6 has a concave shape, when folding the paper SH at the nip N2 of the pair of folding rollers 2, The end portions 61a and 61b are in contact with the deflection of the sheet SH, and the central portion 61c is not in contact with the sheet SH. As a result, as shown by the arrow AR8, the sheet SH is applied with force only at both ends in the width direction, and the wrinkles KL generated at the center of the sheet SH are eliminated. The sheet SH is sent to the nip N2 in a stretched state as shown in FIG. 24B, and the folding process is performed. As a result, wrinkles and damage to the sheet SH to be folded can be prevented.

  Further, since the guide member 6 has a simple shape, the apparatus can be reduced in size and cost can be reduced as compared with the case where the tip of the guide member has a roller shape.

  Further, since the length WG in the width direction of the central portion 61c is shorter than the length WS in the width direction of the minimum sheet to be folded, the sheet SH is used regardless of the size of the sheet SH to be folded. The generation of wrinkles and damage can be prevented.

  Further, since the deformation shape of the paper SH varies depending on the basis weight, the provision of the urging member 34 can prevent damage to the paper regardless of the type of the paper SH regardless of the paper type. Deflection can be appropriately guided to the nip N2.

  Further, since the guide member 6 swings around the fulcrum FC, the drive structure of the guide member 6 can be simplified, and the apparatus can be reduced in size and cost.

  Further, guidance is performed when the sheet SH that is not subjected to the folding process is transported along the transport path TR1 or when the leading end of the sheet SH before forming the first fold is guided to the nip N2 of the pair of folding rollers 2. Since the member 6 is present at the shielding position P61, it is possible to prevent the paper SH from coming into contact with the pair of folding rollers 3 and to obtain good paper passing performance.

  Further, when the first folding process is performed on the paper SH, the guide member 6 moves to the retracted position P62, so that the first folding process can be executed smoothly.

  [Modification of guide member]

  FIG. 25 is a plan view showing a configuration of the guide member 6 in a modification of the present invention.

Referring to FIG. 25, guide member 6 may have an arcuate concave shape as shown in FIG. 25 (a), and central portion 61c may be arcuate. Further, the guide member 6 may be composed of a plurality of members divided in the width direction. For example, as shown in FIG. 25B, the guide member 6 may include guide member pieces 6a, 6b, and 6c formed separately from each other.
The guide member pieces 6a, 6b, and 6c are arranged along the width direction. The guide member piece 6a includes an end portion 61a. The guide member piece 6b includes an end 61b. The guide member piece 6c is provided between the guide member piece 6a and the guide member piece 6b, and includes a central portion 61c. The guide member pieces 6a, 6b, and 6c are connected by a method such as engagement or adhesion.

  [Others]

  The folding guide 4 may be omitted.

  The place where the guide member of the present invention is applied is arbitrary, and may be applied as the folding guide 4.

  The post-processing device 51 only needs to perform post-processing, and instead of Z-folding (tri-folding in which two of the three surfaces have the same area), three-folding processing (the areas of the three surfaces are equal) It is also possible to perform (tri-fold). The post-processing device 51 may further have functions such as a punching function and a stapling process.

  The processing in the above-described embodiment may be performed by software or by using a hardware circuit. It is also possible to provide a program for executing the processing in the above-described embodiment, and record the program on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, or a memory card and provide it to the user. You may decide to do it. The program is executed by a computer such as a CPU. The program may be downloaded to the apparatus via a communication line such as the Internet.

  The above-described embodiment is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Conveying roller pair 2, 3 Folding roller pair 3a, 3b Roller which comprises a folding roller pair 4 Folding guide 4a The front end of a folding guide 6 Guide member 6a, 6b, 6c Guide member piece 7 Paper guide 7a Paper guide opening 8 Arm Part 8a Arm insertion hole 9 Shaft part 21 Discharge tray 31, 33 Fixing part 32, 34 Biasing member 40 Folding device 51 Post-processing device 52 Image forming apparatus main body 61 Guide member tip part 61a, 61b End part of tip part 61c Central portion of tip portion 100 Image forming apparatus 101 CPU (Central Processing Unit)
102 ROM (Read Only Memory)
103 RAM (Random Access Memory)
104 Scanner 105 Network Interface 106 Operation Panel 107 Auxiliary Storage Device 108 Image Forming Unit 109 Post-Processing Control Unit 111 Conveying Roller Pair Control Unit 112 Folding Roller Pair Control Unit 113 Folding Roller Pair Control Unit 114 Folding Guide Control Unit 115 Guide Member Control Unit FC Guide member fulcrum KL Wrinkles N1, N2, N3 Nip P41 Folding guide retracted position P42 Folding guide folding position P61 Guide member shielding position P62 Guide member retracting position P63 Guide member guiding position PO1 Transport in the circumferential direction of the roller 3a Position closest to the path TR1 PO2 Position closest to the transport path TR1 in the circumferential direction of the roller 3b RG Area shielded by the guide member SE sensor SH paper TR1, TR2 Transport path WG Length in the width direction of the central portion WS Minimum width of the paper to be folded

Claims (9)

A pair of folding rollers for folding the paper,
Conveying means for conveying the paper to the pair of folding rollers;
A guide member for guiding the deflection of the paper to the vicinity of the nip of the pair of folding rollers,
The guide member has a plate-like shape, and a tip portion of the guide member, which is an end portion on the downstream side in the sheet conveyance direction, has a concave shape when viewed from the normal direction of the main surface of the guide member. Having a post-processing device. The tip portion includes both end portions in the width direction that are orthogonal to the transport direction when viewed from the normal direction of the main surface of the guide member, and a central portion that is a portion other than the both end portions,
The post-processing apparatus according to claim 1, wherein the both end portions protrude downstream of the central portion in the transport direction.   The post-processing apparatus according to claim 2, wherein a length in the width direction of the central portion is shorter than a length in the width direction of the smallest sheet to be folded.   4. The length in the normal direction of the guide member decreases from the position on the upstream side in the transport direction toward the tip portion by a predetermined distance from the tip portion. Post-processing device.   The post-processing apparatus according to claim 1, further comprising a biasing member that biases the guide member toward a nip of the pair of folding rollers.   The post-processing apparatus according to claim 1, wherein the guide member swings about an axis. And further comprising another pair of folding rollers for performing a first folding process on the paper,
The transport roller pair and the folding roller pair transport the paper along a transport path,
The pair of folding rollers performs a second folding process on the paper on which the first folding process has been performed,
The guide member is movable to a shielding position, and the shielding position constitutes the other folding roller pair and a position closest to the conveyance path in the circumferential direction of one of the rollers constituting the other folding roller pair. The post-processing apparatus according to any one of claims 1 to 6, wherein the guide member is a position where the guide member is shielded from a region between the roller and the position closest to the transport path in the circumferential direction of the other roller. .   The guide member is a retracted position that exists upstream of the shielding position in the transport path in the transport direction, and is further movable to a retract position that exposes the transport path in at least a part of the region. The post-processing apparatus according to claim 7. An image forming apparatus main body for printing on paper;
An image forming apparatus comprising: the post-processing device according to claim 1, wherein post-processing is performed on a sheet printed by the image forming device main body.

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